Very often in translations from German to English the term 'free wheeling diode' for 'Freilauf-Diode' is used. Generally the correct translation for this term would be 'recovery diode'. The usage of the term 'free wheeling' only will be correct in mechanical aspects, e.g. the rear wheel of a bicycle or the clutch of the transmission line of a car.
efreqw
To protect module from freeewheeling during off period with inductive load.
Backward diode
A: A zener is a diode that when connected in the reverse mode current direction it will breakdown to a predetermined voltage any further increasing voltage the breakdown will remain practically the same.
The capacitance of a varicap diode varies as the reverse voltage to the diode changes. As you increase the reverse voltage, the capacitance decreases. And vice versa.